Thrombotic microangiopathy following aortic surgery with hypothermic circulatory arrest: a single-centre experience of an underestimated cause of acute renal failure

Abstract

OBJECTIVES Acute kidney injury (AKI) following surgery involving the heart-lung-machine is associated with high mortality and morbidity. In addition to the known mechanisms, thrombotic microangiopathy (TMA) triggered by the dysregulation of complement activation was recently described as another pathophysiological pathway for AKI following aortic surgery. The aim of this retrospective study was to analyse incidence, predictors and outcome in these patients. METHODS Between January 2018 and September 2019, consecutive patients undergoing aortic surgery requiring hypothermic circulatory arrest were retrospectively reviewed. If suspected, diagnostic algorithm was initiated to identify a TMA and its risk factors, and postoperative outcome parameters were comparably investigated. RESULTS The incidence of TMA in the analysed cohort (n = 247) was 4.5%. Multivariable logistic regression indicated female gender {odds ratio (OR) 4.905 [95% confidence interval (CI) 1.234–19.495], P = 0.024} and aortic valve replacement [OR 8.886 (95% CI 1.030–76.660), P = 0.047] as independent predictors of TMA, while cardiopulmonary bypass, X-clamp and hypothermic circulatory arrest times showed no statistically significance. TMA resulted in postoperative AKI (82%), neurological disorders (73%) and thrombocytopaenia [31 (interquartile range 25–42) G/l], corresponding to the diagnostic criteria. Operative mortality and morbidity were equal to patients without postoperative TMA, despite a higher incidence of re-exploration for bleeding (27 vs 6%; P = 0.027). After 6 months, survival, laboratory parameters and need for dialysis were comparable between the groups. CONCLUSIONS TMA is a potential differential diagnosis for the cause of AKI following aortic surgery regardless of the hypothermic circulatory arrest time. Timely diagnosis and appropriate treatment resulted in a comparable outcome concerning mortality and renal function.

Thrombotische Mikroangiopathien in der operativen Intensivmedizin unter besonderer Berücksichtigung des atypischen hämolytisch-urämischen Syndroms

“…B. mit „human immunodeficiency virus“ [HIV], Hepatitisviren, Zytomegalievirus [CMV], Influenzaviren oder „severe acute respiratory syndrome coronavirus 2“ [SARS-CoV-2] [ 15 ]) identifiziert werden. Auch Tumorleiden, Schwangerschaft oder große Operationen können als Trigger wirken [ 13 ]. Im Gegensatz zum STEC-HUS kann ein aHUS – einmal in Gang gesetzt – selbst nach Kontrolle und anschließender Abwesenheit des auslösenden Triggers (unbehandelt) fortschreiten.…”

“…Über 80 % dieser Patienten erlitten ein z. T. ersatzpflichtiges Nierenversagen. Mithilfe adäquater, aufwendiger Therapie kann jedoch ein Outcome erreicht werden, das dem der Patienten ohne aHUS vergleichbar ist [ 13 ].…”